Menu: Students, then Promote Student.

Read the notice at the top before you start. Move the graduating class to the Alumni page first, so those places are free. Then promote from the highest class downward. Example: move class 4 into class 5, then class 3 into class 4, then class 2 into class 3, then class 1 into class 2. Class 1 is then empty for new students.

Choose Promote from which class, Promote to which class, and the section of the new class. The section list loads from the destination class. Click Filter.

The list shows who will move. Tick the students who should go up. A student who is not moving can be left as not promoted. Click Promote student. Selected students move into the class named in red at the top of the list.